Kevin Anderson's serve is certainly aided by his height. Photo: Adam Hunger, AP

NEW YORK – It sounds like a tall tale, except it’s true.

When 6ft 8in (2.03m) Kevin Anderson faces 6ft 6in (1.98m) Sam Querrey at the US Open on Tuesday, it will be the tallest Grand Slam quarter-final, semi-final or final of the modern era.

On the same day, Diego Schwartzman, standing at just 5ft 7in (1.70m) will be the shortest Grand Slam quarter-finalist since fellow 5ft 7in Peruvian Jaime Yzaga at the 1994 US Open.

In a Grand Slam tournament thrown wide open by the absence of a host of top stars, the US Open has become a contest of extremes.

For Anderson, playing in his second quarter-final in New York, the contrasts between him and the likes of Schwartzman are fascinating.

“If you try to simplify it as much as possible, I guess you could say if a guy who is my size can move around the same as a guy who is much smaller, you would think there are maybe going to be a few more advantages,” said the South African.

“When it comes to the serve especially, the height I can hit on the serve, Diego would have to jump very high to be able to match it.”

At first glance, the raw statistics back him up – Anderson has played Schwartzman twice and won on both occasions.

But the Argentina player has emerged as the king of the return at the US Open, winning 30 of 69 return games – the second-best analysis of the entire tournament.

“Right now, Diego is the best returner on tour when you look at the stats. He’s broken more than anybody else, especially on the returns,” said Anderson.

“From the back, he’s an incredible mover. I think his balance, his change of direction, I think it’s maybe a little bit easier when you’re not as tall.

“Given his size and stuff, he really is able to play great tennis.”

Diego Schwartzman has shown that a lack of extreme height can also be a valuable weapon. Photo: Jason Decrow, AP

Schwartzman struck a Grand Slam blow for the little guy in the third round by downing Croatian giant Marin Cilic, a towering 6ft 6ins and the 2014 US Open champion.

“I hope maybe they can understand tennis is for everyone. It’s not just for the tall guys,” said Schwartzman, the 29th seed who in 2016 lost in the first round of all four Grand Slams.

“Sometimes it’s helping a lot if you are big, because you can serve fast, you can do everything fast on the baseline because you have more, the arms are bigger than me. 

“But I was always like this, and I always try to improve my tennis and try to don’t think about.”

Juan Martin del Potro, who was playing his fourth round later on Monday against Dominic Thiem, remains the tallest man to win a Grand Slam.

The Argentine, nicknamed the “Tandil Tower” after his home town, stands 6ft 6in and won the 2009 US Open.

But there is hope for little big man Schwartzman.

Australia’s Ken Rosewall, nicknamed “Muscles,” won eight Grand Slam titles despite his slender frame of 5ft 7in.

In more recent times, Schwartzman’s compatriot Gaston Gaudio – at 5ft 8in (1.75m) –captured the 2004 French Open.

“It’s not easy, but I am here,” said Schwartzman.